New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1887-01-31
!SECRETIRT UHITNETS REPORT
MORE OBSTRUCTIVE CRITICISM.

UNFAIR AND MISLEADING COMPARISONS BETWEEN
THE DOLPHIN AND ENGLISH DISPATCH BOATS.
To the Editor Of The Tribune.
SIR The generous allotment OF space given 70 me In
your columns controycr misleading statements OF Sec
rotary Wntney annual report encourages to return
to the subject have already considered his comparison
between the American cruiser Atlanta and the Eng
lshbuilt Esnerada. Giovanni Bausan and Mer
sey thnT that can prove even moro concusivelyi In
this letter that tho Sccretarys account of the dispatch
boat Dolphin is wicked distortion OF facts; that he has
deceived the public AMI that 1t Is somebody's duty to
correct his blunders For instance, he says:
The Dolphin AMI the Atlanta having both been completed
and having had trial rps ~ IL possible 10 eompare then m
eisewhefe The Dolphin OF is tons dispaCenent be
Vessels OF 90 the Milan Freueh dsp ch
ws FOR naeatsi pSWer ts ASer
and SURPRISE each 5000 ami the Milan 500 me St h
Dgrh lbs tIh The q s Tne highest ssrd s Of s
Dolphin, resulting from several trials was 1911 kn9ts
i7& s Enois sH Of the Nj M 1 "'
Executive Document No. 153. XLIXth Congress Ia en-
titled letter from the Secretary OF tho Navy. trans
mittiug In response to resolution OF March 5.
1886 information relative to tho Chicago Boston ATTAIN
ia and Dolphin" On page 40 of this document find the
following copy telegram addressed to tho Secretary OF
the Navy. dated NewYork. May %, 1885,:
Dolphin eon'eer.iTs 19urs to-day without mSap Of
diiions we're favorable pressure from 81 to 80 pounds
S pee Sss, 'pp u SG mean so Ct Ss
shin on rrsfO Meflnes
"''"'" '''' President o. the Board.
The italics are my own. II would appear from this
por that the highest speed OF the Dolphin Is not 1911
knots but was at least 80 knots and her horsepower
2.2iO Now in regard the English ships named by the
Secretary have before the official report OF the
when the wonderful speed that no speaks OF was
made md that the Alacrity is credited with having
made mean speed OF 1895 knots per hour for four
hours under forced draft. But fortunately. find in the
fi,ufb Tho NJ NJ
ry on this trial. was 10 feet and 10 inches am there
by enabled show that the speed attained is not fair
measure OF what the vessel could do whom fully laden.
The designed draft Of the Aacrty 10 feet and her
displacement that draft 400 tons 1t thus appears
that on her trial she feet inches Hight Now let
calculate what difference this would make in her dis
placement. and. consequently. in her speed.
In vessels OF very fne lines tho area OF any given
water-liue may DO small 063 OF the circum- |
scribDg rectangle. Assuming that tho Alacriiys |
load watcrne is as fine this land tho assumption Is In
her favor fnl that the LOAF waerne has an area OF
250x32 20 square feet the leng vessel
being $50 feet and beam 325 fee Now cubic foot
OF wafer weighs 135 OF ton hnd that the Aacry WAS
o. =3l7 tons lighter than when equipped for
sea Crhe 2167 /, feet Inchcs reduced feet and
l.400, only weighed on trial li0O-3l71lOs tons.
Now. It Is well known fact TO people who have TO do
OF approximately similar forms vnric directly ms Ger
tain multiple of the horsepower OF the engines. and In
This may be represented BY the formula s. L
where represents the speed in knots per hour; con-
slant mutplier depending upon the model OF the ship
IN ron. 20 Tomnarip me ,raI s,sd and gipsccnt
of the Alacriy wi her designed displacement by the
above formula, lind that when fully laden she can
But i,is X fair that II tho Dolphin was running
light I should make corresP onalng correction and
mud her probable speed nj load draught; hence IL Il
necessary 10 reduce the trials 10 basis OF equality
regards time t4s not FAIR To compare the JDr hours
trial Of the Alacrity with tho sir hours trial OF the Dol
phn. when vessel T. tried for speed she with
clean IRE and everything In the best possible conditions
and the trial proceeds tho fires gradually DO dirty
Admiralty few years 20 reduced the length OF TRIALS
from SIX TO iohr hours making better show OF speed
and 1916 knots for six hours her speed for the
best four hours must have been nj least 1916 knots.
three The mean dransht of Ito Dolphin was fect os
inches only 5 Inches less than her designed drangh
Proceeding Ia the Of the Allcrity ind that her
displacement trial must have been IT, - tons Instead
Reducing the speed In the ratio Of The thirds power
Of the displacement md that the pclphn's sreed at
LOAD draught would hc l5.o7 knots instead OF 1915
X ot- Thus instead oflZ0j-l5ll=2si knots In favor
Of 1oe ESs9 % l n& ih2t 1lg dsTsHS s
only I5.2-l5Os=Ol2 knots Then again. the coal used
miued and hand picked Nixon Navigation coal While
the Dolphin used Cumberland coal mixed with some
than year, hal boon handled 81 least i've ,ncs after
it, first shipment bad made trip 10 the Artic and
IN state OF nencss not at all conduce 10 the best
The secretary also compares the Dolphin with the Sur
PRISE another English vessel He gives her speed
made Ills spec not Tor -1 hours nor for fonr hour. nor
for Que hour bat that the us Knots WAS OF Jour
qlire one 10 be versed IN marine engineering know
tBat mile trial OF steamer Is not fair measure OF
what she can do for several miles on stretch Anybody
who has witnessed between two river steamers can
appreciate this fact steam Is bottled up" until tho
safety valves blow OF; the fires their best
possible condition; the engines are deiuged with
81 ssR 6c@ a, tie a ya ,5ca%eF come; p Ao an
dart- ahead for mile or two at a wonderful pace aud
Now, certainly fair II the speed Of the Surprise
over o mile course Is 10 be compared with time
whcn the surprise could make for several hours How
should II be reduced / ind exactly VIVA, want
lie refers to tas trials Of srrsSos yaoat sst a.,
exceedingly satisfactory He says;
ami the ne amoant Tone tnl Of coal Inc speed
Knots at an average speed OF 96l knots
Now another principle Of marine engineering ia that
rates OF speed vary approximately ~ the cubes
speel OF the 5ilcto with speed for 80 knots gct
certain ratio ana reducing tho measured mile speed OF
the three hours would be not l7.s knots but
l54 knots Moreover the report of the trial OF the sur
peted AT the time had not hal her stepped and
had no stores board. It he taken for granted that
she nowhere her load draught The want az in
formation to the amount OF the deficiency OF draQht
t tSe oad dHass correction Of speed to
same day this vessel had four hours trial under forced
draught hut the report carefully avoids saving wb,t
horse speed developed. but merely state, thai
me eoal per morse to 27s pounds ana
that the steam pressure was 900 pounds per square
inch.
The Surprise was afterward completed and several
attempts were made to obtain high speed load dralgt
These were. for one reason another She
nnally made one grand attempt, when she succeedc
making one run over the measured mile at a speed of
1873 knots and was then obliged to give 1t ND and To into
port on account OF excessive printing her boiler "nJ
other diicultes Comparing the cube OF this speed with
the cubes OF the measured mile OF the sIieito
find that tho possible speed OF the snrn,se
would bo only l44 knots. This looks very lean indeeJ
alongside OF tho l7S knots mentioned In tke serr.iarv's
report The English naval authorities are eydentv noi
very proud OF the surprise for Of her failure
10 make Der designed speed find I'm ,,,sI So
vice papers they have decded not pu, her 10 her m
tended use Admiralty yacht but have fttsd .r M
as gunboat and assigned her to the oblivion of foreip
station. - '"'e'S"
Now, II the Secretary wishes to test the oomnoro,,